The overall objective of the proposed research is to determine the possible role of DNA-dependent RNA polymerase from Agrobacterium tumefaciens in the genesis of crown-gall disease. RNA polymerases from both virulent and avirulent bacteria will be purified by DEAE cellulose and DNA cellulose affinity chromatography, and the purified enzymes characterized by disc gel electrophoresis. The properties of the RNA polymerases in relation to immunological similarities will be compared. Antisera against the purified RNA polymerases will also be used to react with chromatin isolated from crown gall and healthy plant tissue to see if there is a decrease in chromatin RNA production as compared to an untreated chromatin control. It is hoped to acquire evidence from the proposed research for the presence of A. tumefaciens RNA polymerase in bacterial-free tumor tissue.